The number of cables and the spaces between neighboring cables of a flexible flat cable could be selected according to technological demands. The kind of flexible flat cables has advantages of easy-connection, minimizing electrical products, reducing costs and raising production efficiency. The kind of flexible flat cables are widely applied between moving parts and a baseboard, between a PCB board and another PCB board, digital transmission lines of electrical equipment and televisions, etc. A flexible flat cable as a whole with an insulation film (polyimide film or other similar films such as PET film) applied usually has a plurality of single cables. The technology is that: when a traction device such as a rolling device is in operation, a plurality of winding rolls back out a plurality of cables and the cables are applied with insulation films as passing through an station of insulation film, and then the cables are cut according to a length of technological demands and further electrically connected to plug-in components.
As the industry knows, if the spaces between a plurality of cables remain unchanged, then it would result in the following technical problems: first, the volumes of plug-in components electrically connected to the cables become larger so that negative effects for product miniaturization as well as wastes of resources are raised; secondly, risks of short-circuit of cables are increased, especially the possibility of short-circuit becomes high when the spaces between the cables are decreased for reducing the size of plug-in components; third, welding qualities between cables and plug-in components are not reliable because cross-sections of the cables are rounded. Of course, if the parts connecting between the cables and the plug-in components are designed in form of flat shape and the cross-sections of the rest of parts remain in form of rounded shape, then the above technical problems could be solved. By designing the parts connecting between the cables and the plug-in components in form of flat shape, the reliability of connections between the cables and the plug-in components could be achieved and the overall volumes of plug-in components could be reduced. Even though the spaces between the cables are reduced, the phenomena of short-circuit would not occur because of limitations of the plug-in components. The spaces between those neighboring cables are significantly greater than the spaces between the parts connecting the cables and the plug-in components since the cross-sections of the rest of parts remain in form of rounded shape.
From the above descriptions, it is founded that the above technical problems could be completely solved if a calendering device capable of forming segmental flat regions on lengthways of a plurality of cables using a method of segmental calendering are provided. The method of segmental calendering means that a flat region and a round region alternately exist in form of one by one cycle. The flat region is the region generated by the calendering device using the method of calendering, and the rounded region is the non-flat region that is not generated by the calendering device using the method of calendering.
There are messages about the techniques of cable calendering in public Chinese patents. For example, the Chinese patent of public No. CN202070548U discloses “Metal wire calendering device directly driven by servo motors”. The aforementioned technical solution could be achieved by this patent. However, the technical contents of this patent are based on the method of calendering for designing the whole cable in form of flat shape. In other words, this patent does not teach the method of segmental calendering. Similarly, the Chinese patent of public No. CN203591994U discloses “Lead wire rolling mill”, which is not capable of designing cables in form of segmental flat regions.
The number of cables varies within a variety of products. Therefore, it is necessary to manufacture a number of flexible flat cables according to their electrical performances. However, in this condition, it is inconvenient to use flexible flat cables since the specifications of flexible flat cables become complicated and the commonality of flexible flat cables is reduced. Moreover, the spaces between conductors of existing flexible flat cables are controlled and arranged by a spacing-control rod. However, the spaces between conductors are controlled fixedly by the spacing-control rod. It means that a single spacing-control rod is only capable of achieving a single specification of space for flexible flat cables. It is necessary to replace the spacing-control rod with another spacing-control rod if it is desired to producing flexible cables having variable specifications of spaces. Another technical problem is that the changes on the spaces between conductors could not be achieved in a single flexible flat cable, and it results in limitations of structural designs of products. In view of this, the Chinese patent (CN205355693U) discloses “Flexible flat cable conductor controlling means that arranges”. The device of this Chinese patent includes two guide pillar fixed plates, two bush fixed plates, two displacement cylinders, a fixed plate, two component boards, two transmission pieces and an interval wheel set. The left component board is disposed on the top of the left bush fixed plate, the left transmission piece is installed on the left component board, and the left displacement cylinder and the right displacement cylinder are fixed to the fixed plate. The right component board is disposed on the top of the right bush fixed plate, and the right transmission piece is installed on the right component board. The fixed plate is positioned and fixed to the left guide pillar fixed plate and the right guide pillar fixed plate. The left displacement cylinder is connected to the left transmission piece, and the right transmission piece is connected to the right displacement cylinder. The left bush fixed plate and the right bush fixed plate are respectively connected to the left guide piece and the right guide piece through a bearing. The technical solution of this patent is that variable conductions outputted by the cylinder are provided to the component boards, transmission pieces and guide piece for achieving PIN wheel set. The technical solution of this patent achieves the productions of flexible flat cables having variable conductor spaces, but the controlling effects provided the technical solution is not good enough. The outputs of the cylinders could not be controlled precisely and it would result in problems of broken conductors and deviations of spaces.